When stress in early pregnancy are fewer boys born
Stress in the second and third months of pregnancy increases the risk of premature births and can result in a fewer boys being born. This letter from New York University scientists in the journal Human Reproduction. It was already known that stress can affect the duration of pregnancy. This is the first time that stress is brought into relation with the sex of the baby. The researchers analyzed the birth data from more than 600,000 babies born between 2004 and 2006 were born in Chile. On June 13, 2005 an earthquake took place in Tarapaca in Chile. The researchers compared birth data to the residence of the pregnant women at the time of pregnancy. The women closest to the epicenter the earthquake lived during the second and third months of pregnancy had a shorter gestational age compared with women who also lived : average 1.3 days earlier in women who were pregnant two months during the earthquake and 1.9 days earlier in three months. Also, the risk of a premature birth (before 37 weeks) is much larger: Normally in 6 women in 100 babies born prematurely, with the women in earthquake zone rose to 9 at 100. This effect was only found for girls. A second finding was that fewer boys were born to women who lived near the epicenter. The ratio between boys and girls is usually 51 to 49. After the earthquake it was 45 boys to 55 girls. The researchers stress that these data confirm a possible negative effect on the viability of male fetuses. This may be due to the stress hormone cortisol, which affects the function of the placenta.